1091945 has 4 divisors (see below), whose sum is σ = 1310340. Its totient is φ = 873552.

The previous prime is 1091939. The next prime is 1091957. The reversal of 1091945 is 5491901.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5491901 = 17 ⋅323053.

It can be written as a sum of positive squares in 2 ways, for example, as 458329 + 633616 = 677^2 + 796^2 .

It is a cyclic number.

It is not a de Polignac number, because 1091945 - 2¹⁴ = 1075561 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 109190 + ... + 109199.

It is an arithmetic number, because the mean of its divisors is an integer number (327585).

2^1091945 is an apocalyptic number.

It is an amenable number.

1091945 is a deficient number, since it is larger than the sum of its proper divisors (218395).

1091945 is an equidigital number, since it uses as much as digits as its factorization.

1091945 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 218394.

The product of its (nonzero) digits is 1620, while the sum is 29.

The square root of 1091945 is about 1044.9617217870. The cubic root of 1091945 is about 102.9754238031.

The spelling of 1091945 in words is "one million, ninety-one thousand, nine hundred forty-five".